@article {48210, title = {Improvement in oxygen evolution performance of NiFe layered double hydroxide grown in the presence of 1T-Rich MoS2}, journal = {ACS Applied Materials \& Interfaces}, volume = {14}, year = {2022}, month = {JUL}, pages = {31951-31961}, type = {Article}, abstract = {

NiFe layered double hydroxide (NiFe LDH) grown in the presence of MoS2 (rich in 1T phase) shows exceptional performance metrics for alkaline oxygen evolution reaction (OER) in this class of composites. The as-prepared NiFe LDH/MoS2 composite (abbreviated as MNF) exhibits a low overpotential (eta(10)) of 190 mV; a low Tafel slope of 31 mV dec(-1); and more importantly, a high stability in its performance manifested by the delivery of current output for 45 h. It is important to note that this could be achieved with an exceedingly low loading of 0.14 mg cm(-2). The mass activity of this composite (97 A g(-1)) is about 14 times greater than that of the conventional RuO2 (7 A g(-1) ) at eta = 200 mV. When normalized with respect to the total metal content, a mass activity of 1000 A g(-1) (eta = 300 mV) was achieved. Impedance analysis further reveals that the significant reduction in charge-transfer resistance and hence high current density (5 times greater as compared to NiFe LDH at eta = 300 mV) observed for MNF is associated with interfacial adsorption kinetics of intermediates (R-1). Significant enhancement in the intrinsic activity of MNF over LDH has been observed through normalization of current with the electrochemically active surface area. Computational studies suggest that the Ni centers in the composite act as the active sites for OER, which is well-corroborated with the observed postreaction appearance of Ni3+ species.

}, keywords = {Impedance, LDH-MoS2 hybrid electrocatalyst, mass activity, OER, overpotential}, issn = {1944-8244}, doi = {10.1021/acsami.2c06210}, author = {Chakraborty, Soumita and Marappa, Shivanna and Agarwal, Sakshi and Bagchi, Debabrata and Rao, Ankit and Vinod, Chathakudath P. and Peter, Sebastian C. and Singh, Abhishek and Eswaramoorthy, Muthusamy} } @article {48157, title = {Morphology-tuned Pt3Ge accelerates water dissociation to industrial-standard hydrogen production over a wide pH range}, journal = {Advanced Materials}, volume = {34}, year = {2022}, month = {JUL}, pages = {2202294}, type = {Article}, abstract = {

The discovery of novel materials for industrial-standard hydrogen production is the present need considering the global energy infrastructure. A novel electrocatalyst, Pt3Ge, which is engineered with a desired crystallographic facet (202), accelerates hydrogen production by water electrolysis, and records industrially desired operational stability compared to the commercial catalyst platinum is introduced. Pt3Ge-(202) exhibits low overpotential of 21.7 mV (24.6 mV for Pt/C) and 92 mV for 10 and 200 mA cm(-2) current density, respectively in 0.5 m H2SO4. It also exhibits remarkable stability of 15 000 accelerated degradation tests cycles (5000 for Pt/C) and exceptional durability of 500 h (@10 mA cm(-2)) in acidic media. Pt3Ge-(202) also displays low overpotential of 96 mV for 10 mA cm(-2) current density in the alkaline medium, rationalizing its hydrogen production ability over a wide pH range required commercial operations. Long-term durability (\>75 h in alkaline media) with the industrial level current density (\>500 mA cm(-2)) has been demonstrated by utilizing the electrochemical flow reactor. The driving force behind this stupendous performance of Pt3Ge-(202) has been envisaged by mapping the reaction mechanism, active sites, and charge-transfer kinetics via controlled electrochemical experiments, ex situ X-ray photoelectron spectroscopy, in situ infrared spectroscopy, and in situ X-ray absorption spectroscopy further corroborated by first principles calculations.

}, keywords = {Electrochemistry, hydrogen production, intermetallics, water electrolysis}, issn = {0935-9648}, doi = {10.1002/adma.202202294}, author = {Mondal, Soumi and Sarkar, Shreya and Bagchi, Debabrata and Das, Tisita and Das, Risov and Singh, Ashutosh Kumar and Prasanna, Ponnappa Kechanda and Vinod, C. P. and Chakraborty, Sudip and Peter, Sebastian C.} } @article {48094, title = {Potential- and time-dependent dynamic nature of an oxide-derived pdin nanocatalyst during electrochemical CO2 reduction}, journal = {ACS Nano}, volume = {16}, year = {2022}, month = {APR}, pages = {6185-6196}, type = {Article}, abstract = {

Electrochemical reduction of CO2 into valuable fuels and chemicals is a promising route of replacing fossil fuels by reducing CO2 emissions and minimizing its adverse effects on the climate. Tremendous efforts have been carried out for designing efficient catalyst materials to selectively produce the desired product in high yield from CO2 by the electrochemical process. In this work, a strategy is reported to enhance the electrochemical CO2 reduction reaction (ECO2RR) by constructing an interface between a metal-based alloy (PdIn) nanoparticle and an oxide (In2O3), which was synthesized by a facile solution method. The oxide-derived PdIn surface has shown excellent eCO(2)RR activity and enhanced CO selectivity with a Faradaic efficiency (FE) of 92.13\% at -0.9 V (vs RHE). On the other hand, surface PdO formation due to charge transfer on the bare PdIn alloy reduces the CO2RR activity. With the support of in situ (EXAFS and IR) and ex situ (XPS, Raman) spectroscopic techniques, the optimum presence of the Pd-In-O interface has been identified as a crucial parameter for enhancing eCO(2)RR toward CO in a reducing atmosphere. The influence of eCO(2)RR duration is reported to affect the overall performance by switching the product selectivity from H-2 (from water reduction) to CO (from eCO(2)RR) on the oxide-derived alloy surface. This work also succeeded in the multifold enhancement of the current density by employing the gas diffusion electrode (GDE) and optimizing its process parameters in a flow cell configuration.

}, keywords = {CO2 reduction, Electrochemistry, heterostructure interface, in situ mechanism, nanocatalyst}, issn = {1936-0851}, doi = {10.1021/acsnano.1c11664}, author = {Bagchi, Debabrata and Sarkar, Shreya and Singh, Ashutosh Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48098, title = {Strain-enhanced phase transformation of iron oxide for higher alcohol production from CO2}, journal = {ACS Catalysis}, volume = {12}, year = {2022}, month = {SEP}, pages = {11118-11128}, type = {Article}, abstract = {

Conversion of CO2 to higher alcohols (HAs) and higher hydrocarbons (HCs) has a greater advantage compared to C1 products because of their high energy density and wide range of applications in daily life. Despite the immense potential of these chemicals, not much of scientific research has been focused on the conversion of CO2 to HAs. In the present work, we have introduced the concept of strain in designing the material to enhance the CO(2 )to HA performance. We introduced strain in a traditional iron-based catalyst, Fe2O3, by the introduction of indium (In), which facilitates the selective conversion of CO2 to HA. An optimum strain favored a 36.7\% CO2 conversion with a 42\% HA selectivity, and a record yield of 15.42\%. The strain has been tuned further with the introduction of K as a promoter. The introduced strain upon In substitution and K promotion favored the conversion of CO2, which is mapped by powder X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Further, the change in the mechanism upon In incorporation and K promotion has been probed by in situ diffuse reflectance infrared fourier transform spectroscopy, and it is found that the OCHx intermediate, which produces HAs, is more prominent upon In substitution, which favored the enhancement of HA production compared to that of pristine Fe2O3.

}, keywords = {CO2 to HA, Fischer-Tropsch synthesis (FTS), Phase transformation, reverse water gas shift (RWGS) reaction, strain}, issn = {2155-5435}, doi = {10.1021/acscatal.2c0318311118}, author = {Goud, Devender and Churipard, Sathyapal R. and Bagchi, Debabrata and Singh, Ashutosh Kumar and Riyaz, Mohd and Vinod, C. P. and Peter, Sebastian C.} } @article {48088, title = {Structure-tailored surface oxide on Cu-Ga intermetallics enhances CO2 reduction selectivity to methanol at ultralow potential}, journal = {Advanced Materials}, volume = {34}, year = {2022}, month = {MAY}, pages = {2109426}, type = {Article}, abstract = {

Electrochemical CO2 reduction reaction (eCO(2)RR) is performed on two intermetallic compounds formed by copper and gallium metals (CuGa2 and Cu9Ga4). Among them, CuGa2 selectively converts CO2 to methanol with remarkable Faradaic efficiency of 77.26\% at an extremely low potential of -0.3 V vs RHE. The high performance of CuGa2 compared to Cu9Ga4 is driven by its unique 2D structure, which retains surface and subsurface oxide species (Ga2O3) even in the reduction atmosphere. The Ga2O3 species is mapped by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) techniques and electrochemical measurements. The eCO(2)RR selectivity to methanol are decreased at higher potential due to the lattice expansion caused by the reduction of the Ga2O3, which is probed by in situ XAFS, quasi in situ powder X-ray diffraction, and ex situ XPS measurements. The mechanism of the formation of methanol is visualized by in situ infrared (IR) spectroscopy and the source of the carbon of methanol at the molecular level is confirmed from the isotope-labeling experiments in presence of (CO2)-C-13. Finally, to minimize the mass transport limitations and improve the overall eCO(2)RR performance, a poly(tetrafluoroethylene)-based gas diffusion electrode is used in the flow cell configuration.

}, keywords = {(2) reduction, CO, Electrochemistry, Methanol}, issn = {0935-9648}, doi = {10.1002/adma.202109426}, author = {Bagchi, Debabrata and Raj, Jithu and Singh, Ashutosh Kumar and Cherevotan, Arjun and Roy, Soumyabrata and Manoj, Kaja Sai and Vinod, C. P. and Peter, Sebastian C.} } @article {48181, title = {Tuning the hybridization and charge polarization in metal nanoparticles dispersed over Schiff base functionalized SBA-15 enhances CO2 capture and conversion to formic acid}, journal = {Journal of Materials Chemistry A}, volume = {10}, year = {2022}, month = {SEP}, pages = {18354-18362}, type = {Article}, abstract = {

Different Schiff base functionalized SBA-15 materials were synthesized through condensation reactions between 3-aminopropyltriethoxysilane (APTES) and different aldehydes (glutaraldehyde and butyraldehyde) over a mesoporous silica, SBA-15 (APTES-GLU/SBA-15 and APTES-BUT/SBA-15). Both static and dynamic experiments have been used for testing the CO2 capture efficiency of these materials. The hybridization of the N atom in APTES has been tuned from sp(3) to sp(2) upon condensation facilitating optimum CO2 capture in the direct synthesis of APTES-GLU/SBA-15. The undesirable oxides of nitrogen have been removed during the synthesis process to improve the CO2 capture efficiency. These materials were employed as supports for Pd-Ag and Pd-Ni bimetallic systems for the selective conversion of the captured CO2 to formic acid (FA) in 0.5 M KHCO3 solution. The Pd-Ni catalyst system exhibited enhanced CO2 to FA conversion activity compared to other heterogeneous systems, which is similar to 4 times better than that of the Pd-Ag system in this study. The X-ray absorption studies over the catalyst material confirmed that the relatively electron-deficient Ni in Pd-Ni compared to Ag in Pd-Ag favoured higher charge polarization between the metals in the Pd-Ni system enhancing the CO2 to FA conversion. The experimental observations are well supported by the DFT calculations.

}, issn = {2050-7488}, doi = {10.1039/d2ta03690h}, author = {Cherevotan, Arjun and Ray, Bitan and Yadav, Anish and Bagchi, Debabrata and Singh, Ashutosh Kumar and Riyaz, Mohd and Churipard, Sathyapal R. and Naral, Vinay and Kaur, Komalpreet and Gautam, Ujjal K. and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48450, title = {Intrinsic charge polarization in Bi19S27Cl3 nanorods promotes selective C-C coupling reaction during photoreduction of CO2 to ethanol}, journal = {Advanced Materials}, volume = {35}, year = {2023}, month = {FEB}, type = {Article}, abstract = {

Obtaining multi-carbon products via CO2 photoreduction is a major catalytic challenge involving multielectron-mediated C-C bond formation. Complex design of multicomponent interfaces that are exploited to achieve this chemical transformation, often leads to untraceable deleterious changes in the interfacial chemical environment affecting CO2 conversion efficiency and product selectivity. Alternatively, robust metal centers having asymmetric charge distribution can effectuate C-C coupling reaction through the stabilization of intermediates, for desired product selectivity. However, generating inherent charge distribution in a single component catalyst is a difficult material design challenge. Here, a novel photocatalyst, Bi19S27Cl3, is presented which selectively converts CO2 to a C-2 product, ethanol, in high yield under visible light irradiation. Structural analysis through transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy reveals the presence of charge polarized bismuth centers in Bi19S27Cl3. The intrinsic electric field induced by charge polarized bismuth centers renders better separation efficiency of photogenerated electron-hole pair. Furthermore, charge polarized centers yield better adsorption of CO* intermediate and accelerate the rate determining C-C coupling step through the formation of OCCOH intermediate. Formation of these intermediates is experimentally mapped by in situ Fourier-transform infrared spectroscopy and further confirmed by theoretical calculation.

}, keywords = {C-C coupling, charge polarization, CO2 reduction, Ethanol, Photocatalysis}, issn = {0935-9648}, doi = {10.1002/adma.202205994}, author = {Das, Kousik and Das, Risov and Riyaz, Mohd and Parui, Arko and Bagchi, Debabrata and Singh, Ashutosh Kumar and Singh, Abhishek Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} }